Centrifugal pump



June 20, 1939. D. LLEWELLYN 2,163,464

CENTRIFUGAL PUMP Filed April 15, 1937 34 I an" 4/ ATTORNEYS.

Patented June 20, 1939 UNITED STATES PATENT OFFICE GENTBJFUGAL PUMP DonLlewellyn, Huntington Park, Calif.

Application April 15, 1937, Serial No. 137,063

3 Claims.

This invention relates to rotor pumps and particularly pertains tocentrifugal pumps.

In the operation of large centrifugal pumps, such as those used inirrigation and reclamation 5 projects, and in connection with certainengineering construction where it is the present practice to move sand,gravel, and dirt while associated with water, and for rapidtransportation of these products, centrifugal types of pumps are usedthrough which the water and solids are pumped. In the operation of suchpumps it is obvious that the rapid movement of the "solids, which solidsare often gravel and pieces of rock of irregular shape, have an abrasiveaction and rapidly wear away the pump particularly at its throatportions. Various attempts to build pumps which will resist this actionhave been made, such for example as. constructing the pumps in theirentirety of special metals having 20 wear resisting qualities, and alsoby lining the pumps in their entirety with rubber and the like. Theseattempts have been unsatisfactory, however, since in the first instancethe cost of lining the pumps was prohibitive and in the use 25 of anentire rubber lining, it was found that the abrasive action rapidlyimpaired the operation of the pump in that it was necessary to removethe entire lining if any part thereof was worn out. The presentinvention is concerned with 30 a pump structure of the centrifugal typein which special wear resisting elements have been applied at the throatportions of the pump and along the path of travel of the material movingtherethrough, said elements acting to resist abrasion and to alleviatewear throughout the pump throat whereby the life of the pump at thispoint will be materially prolonged and its efilciency increased.

The present invention contemplates the provision of a pump structureincluding an annular pump housing within which a centrifugal rotor ismounted, said housing being equipped at its throat portions with wearsurfaces.

45 in the accompanying drawing in which:

Figure l is'a view in longitudinal central section through the pumpshowing its details of con- The invention is illustrated by way ofexample struction and the points of application of the struction of theimpeller mouth ring-liner and manhole section liner.

Referring more particularly to the drawing, I indicates the pump shaftprovided at its outer end with a coupling flange H and at its inner endwith a reduced threaded portion l2. Mounted upon the shaft III at apoint intermediate its ends is an anti-friction bearing structure l3suitably supported in a journal box l4 mounted upon a base IS. A pump ofthe centrifugal rotor type is associated with the shaft ill in a manmlwhich will be hereinafter described. It is to be understood that theexact design of this pump is immaterial to thepresent invention and thatthe invention is more particularly concerned with the structural partsof the pump which embody the application of specially constructed wearelements at the throat of the pump, as will be hereinafter disclosed.The pump generally speaking comprises a bearing element "5 mounted uponthe shaft III at a point intermediate the bearing structure l3 and apump rotor I! which is secured on to the threaded end of the shaft I0.The rotor I1 is of the centrifugal impeller type having a back wall l8and front wall I9 spaced with relation thereto and forming anintermediate arcuate passageway 20 leading from the circumference of therotor to a central open- -'ing 2| of the pump casing 22 at the oppositeside of the rotor from the end of the shaft I0. The rotor l'l carries aplurality of impeller blades, not illustrated, which operate in space 20occurring between the walls l8 and I9 and act to draw fluid in throughthe throat 2| and discharge it through a tangential outlet in the pumpcasing in the usual manner. A suction or inlet conduit 23 is disposed inlongitudinal alignment with the entire throat 2| of the rotor and issecured to front plate 24 of the pump casing. A

back plate 25 is provided on the casing being dis- 4o posed upon theopposite side of the rotor and in a position to circumscribe the shaftin. The front and back plates 24 and 25 are provided withcircumferentially arranged sets of lugs 26 along their peripherieshaving openings to restricted throat 30 which occurs at the juncture ofthe chamber 28 with the circumference of the rotor 29. At thisparticular point in the travel of the liquids and solids through therotor and into the discharge member 28 there is considerable wear due tothe abrasive action of the solids carried with the liquid passingthrough the pump. It is also desirable at the juncture of thecircumference of the rotor and the circumscribing face of the dischargechamber to create an effective fluid seal between these parts so thatthe tendency of the material passing through the pump would be tocontinue its course rather than to leak around the edges of the rotorand into the pump casing. In order to protect and effectively seal thisarea rubber shoulder liners have been provided. The form of shoulderliner is indicated in Fig. 2 of the drawing and is designated by thereference numeral 3|. The shoulder liner 3| comprises a steel backingring 33 here shown as angular in cross-section, it being understood thatthis ring is in the form of an annulus which seats against acircumferential face 34 and an end face 35 of the wall of the dischargemember 28. These faces are set in from said wall so that acircumferential shoulder 36 will occur at the end of the face 35 and aface 31 will occur at the end of the shoulder 34. The steel backing ring33 does not completely extend to the shoulder 36 and the face 31 and theedges of its sectional elements are feathered outwardly. Vulcanized tothe outer surface of the backing ring 33 is a rubber facing 38. Thisfacing has a curved face 39 which conforms to and merges into thecontour of the inher face of the discharge member 28. The member 38 isin the shape of an annulus and has an inner circumferential face formedwith a fiat circumferential portion 40 and a tapered circumferentialportion 4| which circumscribe the edge of the front wall H) of the rotor29. The shoulder structure 3| is held in position by a series of setscrews 42 which. extend through openings 43 in the wall of the dischargemember 28 and are threaded into the ring 33 which is formed with bosses44 to receive them. It will be evident that due to the fact that theheads of the screws 42 are accessible exteriorly of the discharge member28 the entire structure 3| may be secured in place and compensate forwear of the facing. It is understood that one of the shoulder liners 3|is applied to each side of the throat 30 of the discharge member.

It will thus be seen that in the structures designated as shoulderliners 3| a wear resisting surface will be presented to the abrasiveaction of the material being forced through the pump and that due to thestructure shown it will be possible to readily remove and renew suchfaces as required.

It will be understood that in the construction of centrifugal pumps ofthe type here disclosed it is not practicable to have the relativelymoving faces of the rotor and the case in intimate contact with eachother, since the abrasive action of the sand and water would rapidlywear away these faces and cause leakage. It is therefore usual toprovide a limited amount of tolerance between these faces and to providemeans also tending to move the liquid from between the outer faces ofthe rotor walls l8 and I9 and the front and back head liners 5| and 52respectively. These head liners are interposed between the front plate24 of the pump casing and the rear plate 25 of the pump casingrespectively and are constructed and held in a manner to be hereinafterdescribed. The head liners are designed to be made 'of wear resistingsteel alloy. Attention is directed to the fact that the front head line5| conforms to the contour of the front rotor wall |9 while the backhead liner 52 extends in a plane at right angles to the longitudinalaxis of the pump. The front head liner 5| as indicated in Fig. 1 of thedrawing is shown as formed with a rubber facing 54. In each case, theliners 5| and 52 will be held in position by screws 58 which passthrough the heads 24 and 25 of the motor case and secure the liners inposition. Attention is directed to the fact that the rubber faces of thehead liners extend upwardly and abut against the outer end faces of theshoulder liners 3| to form a tight seal therewith. As before stated, dueto the tolerance between moving parts and the case, there is a tendencyfor water and suspended solids to pass between the surfaces of the caseand the moving parts. abrasive action. In order to move the liquid whichleaks in between the rotor and the head liners the outer faces of thewalls l8 and 9 of the rotor are formed with ribs extending radially. Thewall l8 carries a plurality of ribs I8 and the wall I9 carries aplurality of ribs I9. The ribs l8 conform along their edges to thecontour of the back head liner 52 and a bearing member but are spacedtherefrom as previously described. The long ribs may be cast integralwith the wall of the rotor. The short ribs may be made of special wearresisting material, such as rubber, or of wear resisting steel alloy. Inthe latter instance the alloy is preferably Welded in place.

-When the structure is made of rubber a suitable metal backing isprovided and may be secured to the wall of the rotor by fasteningscrews.

In the present construction the suction end of the rotor hub is designedto assume an abutting relation to the end face of the inlet conduit 23while being slightly spaced therefrom. The contiguous faces of the rotorand the conduit are fitted with ring liners l4 and I5. These ring linersas shown in the enlarged view Fig. 3, comprise a rubber facing 16vulcanized to a steel back plate H by which they are secured inposition. Thus it will be seen that at the points or surfaces betweenwhich abrasion would occur due to the movement of relatively finesuspended solids in the liquid being pumped there are interposedelements having special wear resisting properties and that at the throatof the discharge member where the violent action would take place athroat is fitted with a shoulder .tending to resist this action.

In operation of the present invention the pump is assembled as shownwith the various liners in position as indicated in Fig. 1. Attention isdirected to the fact that at all of the vulnerable points whereexcessive wear between moving parts occurs the opposing surfaces arefitted with special wear resisting elements. In a pump of this generaltype the shaft Ill is driven at a relatively high rate of speed and alarge amount of liquid and materials are moved through the pump. Forexample, the inlet conduit 23 may have a diameter of more than two feet.It will therefor be appreciated that a large volume of material will bedrawn through the pump and that in this material may be associated sand,gravel, and boulders which are being moved. As these suspended and movedarticles are drawn toward the periphery of the rotor 29 they will bethrown across the chamber of the discharge member 28 and their forcewill be to a great extent spent These solids thus produce an H which itpasses into a space 8| occurring between the back wall I8 of the rotorand the head 25 of the pump casing. The force of this supplyof watertends to move the accumulated liquid and solids outwardly through thisspace, the said materials having seeped in .between the moving.

the liquid and material tend to form eddies which rapidly abraid pits inthe surfaces so that after such abrasion has been started the efliciencyof the pump is readilydecreased. Attention is directed to the fact thatthe rotor and its casing must fit together with a certain amount oftolerance in order to efflciently operate, and if this tolerance greatlyincreases due to excessive wear of the parts the efllciency of the pumprapidly drops. For example, in. a pump of the general dimensions shownin the present case having a rotor substantially six and one-half feetin diameter the tolerance between parts is approximately one-eighth ofan inch, but if this space widens to as much as one-quarter of an inchthe maximum efllciency of the pump is reduced. By providing the wearresisting surfaces at pointswhere adjustment of clearance is requiredthe adjustment is more readily obtained and the efficiency of the pumpis greatly prolonged without requiring the replacement of worn parts. Inoperation of a pump of this type as ordinarily constructed the velocityof the moving material as it passes outwardly from the space 8| betweenthe back wall l8 of the rotor and the head 25 of the casing acts todirectly cut away a large crevice inthe circumscribing face of the wallof the discharge member 28. With the special wear shoulders 3| as hereinprovided this wearing action is materially diminished,

It will thus be seen that the pump structure here disclosed is designedto provide a pump of I eflicient operation while at the same timefitting it .with special wear resisting elements disposed at vulnerablepoints between the moving parts of the apparatus, at which points thenecessary adjustment of parts will be maintained while resisting theusual wear occurring, thus insuring that the pump will be maintainedwith its parts in adjustment for a longer period of time and that theefficient operation of the pump will thus be sustained.

While' I have shown the preferred form of my invention, as now known tome, it will be understood that various changes might be made in thecombination, construction, and arrangement of parts, by those skilled inthe art, without departing from the spirit of the invention as claimed.

Having thus described my invention, what I claim and desire to secure byLetters Patent is;

1. In a centrifugal pump a circular casing having an axial inlet and acircumferential outlet chamber substantially circular in cross-sectionand being formed with an inner circumferential opening, a rotor withinsaid casing having spaced side walls forming a passageway communicatingaxially with the axial inlet and radially with the circumferentialopening, the side walls of the outlet chamber overhanging thecircumferences of said rotor walls and annular shoulder liners carriedby the casing and interposed between the overhanging shoulder of thewalls of the outlet chamber and the circumferential faces'of the rotorwalls, said shoulder liners being made of rubber to resist abrasion.

2. In a centrifugal pump a circular casing having an axial inlet and acircumferential outlet chamber substantially circular in cross-sectionand being formed with an inner circumferential opening therearound, arotor within said casing having spaced side walls forming a passagewaycommunicating axially with the axial inlet and radially with thecircumferential opening, the side walls of the outlet chamberoverhanging the circumferences of said rotor walls, annular shoulderliners carried by the casing and inter,- posed between the overhangingshoulder of the walls of the outlet chamber and the circumferentialfaces of the rotor walls, said shoulder liners being made of rubber toresist abrasion and having metal backing plates therein, and' meanscarried by the casing to engage the backing plates and to hold theliners in position.

3. In a centrifugal pump a circular casing having an axial inlet and acircumferential outlet chamber substantially circular in cross-sectionand being formed with an inner circumferential opening therearound, arotor within said casing having spaced side walls forming a passagewaycommunicating axially with the axial inlet and radially with thecircumferential opening, the side walls of the outlet chamberoverhanging the circumferences of said rotor walls, annual rubbershoulder liners carried by the casing and interr posed between theoverhanging shoulder of the walls of the outlet chamber and thecircumferential faces of the rotor walls, said shoulder liners havinga'portion interposed between the circumference of a rotor wall and thewall of the casing and a flange portion substantially at right anglethereto and being set in to the face of the wall of the chamber wherebya peripheral throat portion is provided along and through the innercircumferential opening of the'casing, a metal backing plate forming apart of said shoulder liner, said plate being angle-shaped, the separatelegs of the plate extending along the two portions of the liner andfasteningmeans carried by the easing and engaging the backing plate tohold the liner in position.

DON LLEWELLYN.

